Bifocal distance sound concentrator



March 10, 1936. p HARMER I 2,033,337

BIFOCAL DISTANCE SOUND CONCENTRATOR Filed Nov. 21, 1929 INVENTOR. 1%4/ X2 flow W ATTORNEY,

Patented Mar. "10, 1936' UNITED STATES PATENT OFFICE nrrocar. DISTANCE scum) cononmnaroa Paul B. Harmer, Los Angeles, Calif. Almlicatlon November 21. 1929, Serial No. 403,897 10 Claims. (01. 181-05) placing the microphone adjacent the sound 15 source. Also in military and naval operations my device will prove valuable as a means of deter-- mining the exact location of sound given out by sources such as airplane motors, submarines and the like. By the use of nested horns as herein- 20 after described, a much increased sensitivity is obtained in directional determination.

Fig. 1 is a diagrammatic view of the sound concentrator showing the paths of various sound waves emanating from a common point. 25 .Fig. 2 is a front elevation.

Fig. 3 is a rear elevation. Fig. 4 is'a side elevation partly in section. Figure 1 is a diagrammatic cross-section of a preferred form of my device showing several 30 horns placed inside each other in such manner so as to assist one another in concentrating to point A the sound waves or impuises,-moving from a sound source designated inthe drawing as F at a distance outside the concentrator, along the 35 axis CC and coming within the perimeter of the largest horn.

Numerals i, 2, 3, 4, and 5 represent 'the inside surface of the flve horns, used in this particular nfodel, and their relative positions; they areset at such an angle so as to reflect sounds SI to S5 moving from F to A or from A to F. The exact shape of the horns I to 5 inclusive may of course vary, but I have found that the most'efflcient vcircular openings of i, 2, 3, l, and 5.

Such a device has a wide shape for most purposes is an ellipsoid of revoside as illustrated by sound impulse Ui striking -6 and being reflected back to the outside.

Figure 2 illustrates the front elevation of the Supports ll, I2, 13,", i5, and ii are for the purpose of 5 holding the horns rigid, preferably of a nonmetallic, nonresonating material.

Figure 3 represents the rear elevation and letters'B, D, E, and F are openings in the back 6 to the tuning compartments if used, numerals 10 39, 40, 4|,and 42 designate sliding covers to regulate at will the size of B, D, E, and F. These variable parts are necessary to keep the horn from resonating at various pitcheson prolonged tones ,and are used to tune the concentratorin order to maintain a constant quality of tone.

A is the compartment in which the receivin or reproducing instrument is placed. A sound nonconduoting cover can be used in conjunction with the Bifocal distance sound concentratorfor the purpose of reducing the number of active horns. Presuming it was desirable to stop reception through horn I to decrease, volume this sound nonconduoting cover would be placed over the opening of this section, see Figure 4, numeral H which represents the sectional side view. If fewer horns were required more sections of cover could be used until the desired volume would be had. If desired, this cover could be removed and maximum. reception continued.

In addition to the model described above having five horns, variations thereof may be constructed on the same principles, having one, two, three, vfour, six or more horns to meetdiflerent .reception'and reproducing requirements, such as size of perimeter, length of horn, distance from focal sound source as welias volume desired from a weak or powerful sound.

While the form of my invention shown herein 40 is fully capable of performing the functions claimed, it is to be understood that I do not limit myseli thereto but that the scope of my inv'entlonis to be determined by the appended claims.

What I claim is:

1. A sound concentrator comprising a series of nested horns whose outside circular openings all he in the same plane, the length, diameter and degree of curvature of each horn being less than that of the next outer horn to cause each sound wavefalling thereon to be reflectedonly once before reaching the common point of concentration of the horns and means for supportingsaid horns in spaced relationship about a common axis.

therein 01 'a series of nested'horns the length,

2 A sound concentrator comprising: a series oi nested horns having a common point of sound concentration the size and length 0! each horn beingless than that of the next outer horn; means for supporting said horns so that their outeropenings alllie in the same plane with their longitudinal axes along a central axis in line with a point of sound source and said point of common sound concentration.

4 3. A sound concentrator comprising a series of nested horns whose outside openings all he in the same plane, the length, diameter and degree of curvature of each horn being less than that of the next outer horn and means for supporting said horns in spaTcedrelationshi about a common axis.

4. A'sound concentrator comprising .a series or nested horns having a common point of sound concentration, the length, diameter and degree of curvature of. each horn being less than that of the next outer horn to cause each sound wave falling thereon to bereflected only once before reaching the common point of concentration of the horns and means for supporting said horns in spaced relationship about a common .axis.

5. The combination with walls forming a sound concentration chamber having an aperture diameter and degree of curvature of each horn being less than that oi the next outer horn said horns having a common axis in line with said aperture.

s. The combination with walls forminga sound concentration chamber of a relatively large horn associated therewith having a series of. smaller horns nested therein, the outer perimeter of said hornsbeing in a common plane.-

outer hem and disposed therein means for supporting said hornsin spaced relationship'about a common axis with their outer openings in one plane, all of said horns being of such a curvature and spaced relative to each other as to cause.

sound waves fallingthereon from a given source to be reflected but once before reaching a given point at said rear wall.

8. A soundconcentrator comprising: a series of nested horns the outer of which is connected toa sloping back wall having .a plurality of apertures therein means for supporting said horns in spaced relationship about a common axis with their outer openings in one plane; and slidable means associated with said back wall for varying the size of said apertures. v

9. A soundconcentrator comprising: a series of nested horns of progressively smaller diameter, length and degree of curvature from the outermost horn to the innermost horn and means for supporting said horns one within the other with their outside openings in one plane so that they 'will reflect to a common concentration point spaced relationship abouta common axis with the outside openings of 'said'horns all lying in 3 a plane perpendicular to said axis.

PAUL R. HARMER' 

